Industrial plant having safety-relevant area

ABSTRACT

In an industrial plant for producing or processing liquid, red-hot or hot metal a safety-relevant area is formed in the direct vicinity of the liquid or red-hot metal and the presence of a person is at least periodically not allowed. A detector unit is provided for the surveillance of the area, detecting electromagnetic radiation emitted by a present person or identifying the absence of electromagnetic radiation blocked by a present person. Furthermore, an evaluation unit is able to detect the presence of a person from the output data of the detector unit, and for a control unit which is connected to the evaluation unit. If a person is present in the safety-relevant area, the control unit automatically initiates an action acting against the presence of the person. By forming a plurality of safety-relevant areas having different danger levels, gentle stopping of the industrial plant is made possible.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application of InternationalApplication No. PCT/EP2007/056214 filed Jun. 21, 2007, which designatesthe United States of America, and claims priority to German ApplicationNo. 10 2006 032 955.4 filed Jul. 17, 2006, the contents of which arehereby incorporated by reference in their entirety.

TECHNICAL FIELD

The invention relates to an industrial plant for producing or processingliquid, incandescent or hot metal, particularly a blast furnaceinstallation or a rolling mill in which a safety-relevant area, in whichthe presence of a person is not permitted at least temporarily, isformed in the direct environment of the liquid or incandescent metal.

BACKGROUND

Devices for the surveillance of spatial areas are known, e.g. from DE101 63 534 A1, DE 102 21 578 A1 and DE 10 2004 047022 A1. In thiscontext, sensors are used which provide three-dimensional informationabout the monitored area. The principle of the 3D CMOS sensor is thusbased on the fact that a laser and an electronic lock are exactlysynchronized. The lock opens exactly with the emission of the laserpulse. The extremely short light pulse illuminates an obstacle—ifpresent—and the reflected light pulse impinges on the 3D CMOS imageconverter. The sensor registers the propagation times which areevaluated as a measure of the distance and the shape of the obstacle. Alight-emitting diode or a laser can be used as transmitter. One pixel ofthe CMOS sensor can in each case comprise one photodiode and anassociated pixel capacitor which is discharged by illumination of thephotodiode when the time window is open.

Modern industrial plants must be planned and operated in such a mannerthat the risk to persons is reduced to a minimum. As a rule, therefore,certain plant sections with high hazard potential are partitioned off orthe access to some areas is blocked. For this purpose, protective gridsand gates can be provided.

For the partitioning or control of hazardous areas around machines or insimple industrial plants, so-called switching mats or also opticalsystems, e.g. light barriers are also known. Like fences with accessgates, switching mats have high constructional complexity. Optical orradiation-based systems are not taken into consideration under extremeenvironmental conditions.

SUMMARY

According to various embodiments, a safety-relevant area can be securedand checked in a constructionally simple manner in an industrial planthaving a very strong heat emission, namely in an industrial plant forproducing or processing liquid, incandescent or hot metal.

According to an embodiment, an industrial plant for producing orprocessing liquid or incandescent metal, particularly a blast furnaceinstallation or rolling mill in which a safety-relevant area, in whichthe presence of a person is not permitted at least temporarily, isformed in the direct environment of the liquid or incandescent metal,characterized by a surveillance device for the safety-relevant area, maycomprise: a) a detector unit which detects electromagnetic radiationemanating from a present person or the absence of electromagneticradiation blocked out by a present person, wherein the detector unit isbased on a combination of at least two of the following detectortypes:—a motion detector,—a light barrier,—a video camera or a CCDcamera,—a thermal camera,—a combination of light transmitter andsemiconductor matrix sensor, particularly in CMOS technology, b) anevaluating unit which detects from output data of the detector unit thepresence of a person, and c) a control unit connected to the evaluatingunit, which, when a person is present in the safety-relevant area,automatically initiates an action acting against the presence of theperson, and d) a plant control device which is connected to the controlunit in such a manner that when an endangered person is detected, theplant control device can automatically carry out an intervention in theplant operation which reduces the hazard, particularly in real time.

According to a further embodiment, the detector unit can be based on atleast one and preferably on a combination of several of the followingdetector principles:—1-D sensor or line scan, particularly lightbarrier,—2-D sensor or area scan, particularly light curtain or 2Dcamera,—3-D sensor, particularly comprising a light transmitter, asemiconductor matrix sensor with one photodiode and one capacitor perpixel for integrating the reflected transmitter light and a delaydetermining unit. According to a further embodiment, the detector unitmay generate an image from the safety-relevant area and the evaluatingunit may carry out image processing. According to a further embodiment,the image processing may carry out object or pattern recognition,preferably on the basis of a neural network, so that a person can bedistinguished from a non-human object. According to a furtherembodiment, there may be no protective grids or fences or there may befewer protective grids or fences for securing the safety-relevant areathan would be necessary for ensuring adequate or prescribed safetywithout surveillance device. According to a further embodiment, at leastone further safety-relevant area may be formed which differs or differin its/their risk potential from the first-mentioned safety-relevantarea and the further safety-relevant area or areas can be monitoredseparately for the presence of a person by the surveillance device.According to a further embodiment, at least one of the safety-relevantareas may have a danger level of between “maximum hazard” and “nohazard”. According to a further embodiment, the intervention can becarried out with its intensity depending on the risk potential of thesafety-relevant area in which the forbidden person has been detected.According to a further embodiment, the intervention, in the case of arolling mill, may include a reduction of the rate of rolling or ofthroughput and/or a stopping of the mill train. According to a furtherembodiment, the intervention may include in the case of a steel mill orblast furnace a delay and/or an interruption of an opening of thefurnace. According to a further embodiment, the industrial plant maycomprise an input device for establishing a locking area by theoperating personnel of a control room.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of an industrial plant will be explained ingreater detail with reference to the drawing in the text which follows.

The single FIGURE shows an embodiment of a continuous-casting plant withhot rolling mill in a greatly diagrammatic form.

DETAILED DESCRIPTION

As mentioned above, according to various embodiments, a surveillancedevice for the safety-relevant area, may comprise:

-   -   a detector unit which detects electromagnetic radiation        emanating from a present person or the absence of        electromagnetic radiation blocked out by a present person,    -   an evaluating unit which detects from output data of the        detector unit the presence of a person, and    -   a control unit connected to the evaluating unit, which, when a        person is present in the safety-relevant area, automatically        initiates an action acting against the presence of the person.

According to various embodiments, a radiation-based surveillance devicecan guarantee the required safety for a safety-relevant area also inindustrial plants having a high heat and infrared radiation emission.The various embodiments are thus breaking with a technical prejudice.The experts have hitherto not considered such detector units for blastfurnace installations or rolling mills. Instead, a great amount ofeffort is expended with mechanical access barriers now as before. Thevarious embodiments have the advantage that elaborate mechanicallatching devices such as innumerable electrically latched gates in afence etc. are not necessary for guaranteeing adequate safeguarding ofpersons. Dispensing with or reducing the number of such protective gridsand/or gates also has considerable advantages in the case of plantmaintenance because these fences and gates do not then impede the accessto the plant.

The detector unit can be preferably based on at least one of thefollowing detector types:

-   -   a motion detector,    -   a light barrier,    -   a video camera or a CCD camera,    -   a thermal camera,    -   a combination of light transmitter and semiconductor matrix        sensor, particularly in CMOS technology.

The combination of at least two of the aforementioned detector types inthe detector unit may be particularly preferred as a result of which aparticularly high safety standard can be achieved.

It can also be of special advantage if detector principles withdifferent detection dimensionality are used in the detector unit suchas, e.g. a one-dimensional sensor or a line scan, particularly a lightbarrier, and/or a two-dimensional sensor or an area scan, particularly alight curtain or a 2D camera, and/or a three-dimensional sensor, thelatter comprising, in particular, a light sensor, a semiconductor matrixsensor with one photodiode per pixel and a capacitor for integrating thereflected transmitter light and a delay determining unit.

According to a further embodiment, the detector unit is set up forgenerating an image from the safety-relevant area and the evaluatingunit processes the image. In the image processing, an object or patternrecognition can preferably be carried out, preferably based on a neuralnetwork so that a person can be distinguished from a non-human object.

Apart from the detection of a hazard to persons, this also makes itpossible to detect other unplanned or irregular movements, e.g. byvehicles or falling parts, in the plant.

According to a further development, at least one further safety-relevantarea is formed in the industrial plant which differs or differ inits/their risk potential from the first-mentioned safety-relevant areawherein the further safety-relevant area or areas can be monitoredseparately for the presence of a person by the surveillance device. Inthis context, at least one of the safety-relevant areas preferably has adanger level of between “maximum hazard” and “no hazard”.

According to another embodiment, the control unit is connected to aplant control device so that, when an endangered person is detected, theplant control device can automatically carry out an intervention in theplant operation which reduces the hazard, particularly in real time,online and/or without the interposition of human inputs.

In this context, it is of quite particular advantage if the interventioncan be carried out with its intensity depending on the risk potential ofthe safety-relevant area in which the forbidden person has beendetected. This advantageously results in the possibility for a “gentle”stopping of the plant, e.g. by initially reducing the rate of rolling orthroughput in a rolling mill when a person is detected in an area ofmedium risk potential and only reducing the rate of rolling orthroughput to zero, i.e. stopping the plant, if the person penetratesthe area of maximum risk potential.

In a steel mill or a blast furnace, the response to a person penetratingcan consist of a delay and/or a complete interruption of an opening ofthe furnace.

The industrial plant also may preferably have an input device forestablishing a locking area by the operating personnel of a controlroom. The operating personnel can thus flexibly define, for instancewithin an area of medium risk potential, a section, the so-calledlocking area which temporarily has a higher or the maximum risk level,for instance because a machine with increased risk potential istemporarily stored in this area.

The single FIGURE shows as the industrial plant 1 a continuous-castingplant with hot rolling mill in a greatly diagrammatic form. Theinvention can also be applied in a cold rolling mill where the steel,e.g., is hotter than 100° C.

Liquid metal 2, e.g. iron, is conducted through a funnel mold 3 anddeflection rollers from a vertical feed direction to a horizontal feeddirection. In the horizontal, the ribbon 6, which is still glowing,passes through several rolling stands 5 after it has been heated in aninduction furnace 7.

Around the continuous-casting and rolling area of the industrial plant1, several safety-relevant areas B1, B2, B3 are formed which aremonitored in each case separately by themselves by a surveillancedevice. The monitoring has the aim of finding out which processes occurin the respective area B1, B2, B3 and, in particular, whether a personhas penetrated in forbidden manner in the respective area B1, B2, B3,who would be exposed to an unacceptable hazard in this area. Thesafety-relevant areas comprise a secure area B3, a less hazardous areaB2 and a very hazardous area B1.

The surveillance device, particularly for the safety-relevant areas B1and B2, comprises a detector unit having a number of differentdetectors. These are a CCD camera or video camera 10 which generates atwo-dimensional image (projection) of the area monitored, furthermore athree-dimensional image sensor having a combination 12 of a lighttransmitter and a semiconductor matrix sensor arranged in the immediatevicinity of the light transmitter, furthermore a motion detector 14 anda light barrier 16A, 16B. The motion detector 14 is based, for example,on the so-called pyroelectric effect. The light barrier can be operatedwith visible or invisible light. As the 3-D sensor, for example, asemiconductor matrix sensor in CMOS technology is used such as isdescribed, for example, in DE 10 2004 047022 A1, DE 101 63 534 A1 or DE102 21 578 A1.

Due to the interaction of these different detector types and detectorprinciples, an evaluating unit 22 which is supplied wirelessly or inwire-connected manner with the output data of the said detectors, candetect in a particularly reliable manner the presence of a person in thesafety-relevant area B1 or B2 and distinguish him for example fromartifacts generated from the continuous-casting or rolling area due tointerference radiation. To further secure the person detection process,an object and pattern recognition of the image generated by the detectorunit also takes place in the evaluating unit 22 by means of a neuralnetwork.

The different safety-relevant areas B1, B2 can be separately monitoredas images in that there is a separate camera or a separate matrixdetector for each area, i.e. that the different areas B1, B2 are definedand specified by the respective acquisition cone of the associateddetectors. As an alternative, the areas B1, B2 can be monitored jointlyby a common detector, preferably a 3-D sensor, wherein the distinctionwhether there is an unwanted person in the area B1 or in the area B2 canthen be carried out as an evaluation by means of position data which aresupplied by the detector.

In a control unit 24 functionally following the evaluating unit 22, forthe case where an unwanted person is detected in a safety-endangeredarea B1 or B2, an action acting against the presence of this person isinitiated. This can consist in that the person is first warned, e.g. fora short time, by a light or tone signal, e.g. by means of a loudspeaker26. At a higher escalation level, the control unit 24 acts directlyfunctionally on the plant control device 30 which, together with theevaluating unit 22 and the control unit 24, is accommodated in a controlroom 20 of the industrial plant 1. In the case where the person, after ashort audible warning time, is still located in the hazardous area B1 orB2, the mill train 5 is stopped or the rate of throughput, respectively,is reduced. This is done without requiring an intervention by theoperating personnel.

In the case where the safety-relevant areas B1, B2 are monitored by a3-D sensor, in particular, it is of special advantage that the operatingpersonnel in the control room 20 can establish via an input device 40 alocking area V which is temporarily graded as having an increased riskpotential. The locking area V shown can thus be temporarily graded inthe risk potential of the area B1, for example, i.e. if a person entersthe locking area V, an action of the highest escalation level isimmediately triggered, e.g. the immediate stopping of the rolling mill.

According to one variant, a thermal camera is used as camera, whichresults in the advantage that it is not only persons in unwanted areaswhich can be identified but also other unusual temperature variationscan be detected in the industrial plant, for instance if liquid metalemerges at an unwanted location or hot iron parts have fallen down.

1. An industrial plant for producing or processing liquid orincandescent metal in which a safety-relevant area, in which thepresence of a person is not permitted at least temporarily, is formed inthe direct environment of the liquid or incandescent metal, comprising asurveillance device for the safety-relevant area, comprising: a) adetector unit which detects electromagnetic radiation emanating from apresent person or the absence of electromagnetic radiation blocked outby a present person, wherein the detector unit is based on a combinationof at least two of the following detector types: a motion detector, alight barrier, a video camera or a CCD camera, a thermal camera, and acombination of light transmitter and semiconductor matrix sensor,particularly in CMOS technology, b) an evaluating unit which detectsfrom output data of the detector unit the presence of a person, and c) acontrol unit connected to the evaluating unit, which, when a person ispresent in the safety-relevant area, automatically initiates an actionacting against the presence of the person, and d) a plant control devicewhich is connected to the control unit in such a manner that when anendangered person is detected, the plant control device canautomatically carry out an intervention in the plant operation whichreduces the hazard.
 2. The industrial plant according to claim 1,wherein the detector unit is based on at least one of the followingdetector principles: 1-D sensor or line scan or light barrier, 2-Dsensor or area scan or light curtain or 2D camera, 3-D sensor.
 3. Theindustrial plant according to claim 1, wherein the detector unitgenerates an image from the safety-relevant area and the evaluating unitcarries out image processing.
 4. The industrial plant according to claim1, wherein the image processing carries out object or patternrecognition so that a person can be distinguished from a non-humanobject.
 5. The industrial plant according to claim 1, wherein there areno protective grids or fences or there are fewer protective grids orfences for securing the safety-relevant area than would be necessary forensuring adequate or prescribed safety without surveillance device. 6.The industrial plant according to claim 1, wherein at least one furthersafety-relevant area is formed which differs or differ in its/their riskpotential from the safety-relevant area and that the furthersafety-relevant area or areas can be monitored separately for thepresence of a person by the surveillance device.
 7. The industrial plantaccording to claim 6, wherein at least one of the safety-relevant areasand the at least one further safety-relevant area has a danger level ofbetween “maximum hazard” and “no hazard”.
 8. The industrial plantaccording to claim 7, wherein the intervention can be carried out withits intensity depending on the risk potential of the safety-relevantarea in which the forbidden person has been detected.
 9. The industrialplant according to claim 1, wherein the intervention, in the case of arolling mill, includes at least one of a reduction of the rate ofrolling or of throughput and a stopping of the mill train.
 10. Theindustrial plant according to claim 1, wherein the intervention includesin the case of a steel mill or blast furnace at least one of a delay andan interruption of an opening of the furnace.
 11. The industrial plantaccording to claim 1, comprising an input device for establishing alocking area by the operating personnel of a control room.
 12. Theindustrial plant according to claim 1, wherein the industrial plant is ablast furnace installation or rolling mill.
 13. The industrial plantaccording to claim 1, the plant control device automatically carries outthe intervention in the plant operation which reduces the hazard in realtime.
 14. The industrial plant according to claim 1, wherein thedetector unit is based on on a combination of several of the followingdetector principles: 1-D sensor or line scan or light barrier, 2-Dsensor or area scan or light curtain or 2D camera, 3-D sensor.
 15. Theindustrial plant according to claim 14, wherein the 3-D sensor comprisesa light transmitter, a semiconductor matrix sensor with one photodiodeand one capacitor per pixel for integrating the reflected transmitterlight and a delay determining unit.
 16. The industrial plant accordingto claim 2, wherein the 3-D sensor comprises a light transmitter, asemiconductor matrix sensor with one photodiode and one capacitor perpixel for integrating the reflected transmitter light and a delaydetermining unit.
 17. The industrial plant according to claim 4, whereinthe object or pattern recognition is carried out on the basis of aneural network.
 18. A method for securing a safety relevant area in anindustrial plant for producing or processing liquid or incandescentmetal, in which safety relevant area the presence of a person is notpermitted at least temporarily, comprising the steps of: a) detectingelectromagnetic radiation emanating from a present person or the absenceof electromagnetic radiation blocked out by a present person using adetector unit which is based on a combination of at least two of thefollowing detector types: a motion detector, a light barrier, a videocamera or a CCD camera, thermal camera, and a combination of lighttransmitter and semiconductor matrix sensor, particularly in CMOStechnology, b) detecting from output data of the detector unit thepresence of a person, and c) when a person is present in thesafety-relevant area, automatically initiating an action acting againstthe presence of the person, and d) when an endangered person isdetected, automatically carrying out an intervention in the plantoperation which reduces the hazard.
 19. The method according to claim18, further comprising the step of generating an image from thesafety-relevant area and carrying out image processing.
 20. The methodaccording to claim 18, wherein the image processing carries out objector pattern recognition so that a person can be distinguished from anon-human object.